GRADUATE RESEARCH SPOTLIGHTS

Whether hooved or flippered, mammals are at the forefront of current graduate research in the Condon Fossil Collection. Read on for updates from three of our PhD candidates.

Evolution of Pinnipeds

Kellum Tate-Jones studying a fossil pinniped collection Pinnipeds—true seals, eared seals, and walruses—first appeared on the Northwest coast of North America over 25 million years ago. Since then, the lineage has spread to inhabit coastal ecosystems across the globe. PhD candidate Kellum Tate-Jones’ research is addressing outstanding questions about the relationships of fossil pinnipeds to one another and the effects of both modern and deep time climate change on their geographical distribution. In 2020, Tate-Jones published a description of a new fossil pinniped, Eodesmus condoni, from the Oregon coast, along with coauthors Carlos Peredo, Christopher Marshall, and museum paleontologist Samantha Hopkins. Eodesmus condoni is the latest described species from the extinct pinniped family Desmatophocidae—a family first identified by University of Oregon professor and paleontologist Thomas Condon in the 1800s.

Niche Partitioning and Community Change

Niche partitioning is the process by which competing species use their environment differently in a way that helps them to coexist. To better understand how ungulates, or hooved mammals, responded to past climatic changes, PhD candidate Dana Reuter is investigating whether they partitioned plant-food resources (ate different diets) and how those ecological trends changed through time. Ungulates are key herbivores in terrestrial ecosystems and today many are threatened with extinction. Understanding how ecosystem change affected ungulates in the deep past will increase our ability to help species survive an thrive today. To see if certain species preferred particular environments, Reuter is analyzing the stable carbon and oxygen isotope composition of fossil tooth enamel from ungulates found in three Oregon geological formations. New local isotopic data collected for this study will be a powerful tool for reconstructing Oregon’s herbivore community structure over the past 20 million years.

Changing Landscapes and Mammalian Evolution

A great number of extinct mammals are known from the sediments of Oregon and are thought to have evolved in response to factors like climate and landscape change—factors that had an effect on biodiversity throughout Oregon’s deep past. PhD candidate Amanda Peng is investigating landscape change, climate, and mammalian evolution in past and present day in Oregon and across North America to better understand these relationships.